Introduction of copper electroplating into a manufacturing fabricator

The introduction of copper electroplating into IBM's manufacturing fabricators in E. Fishkill, New York, and Essex Junction, Vermont is discussed. Although electroplating has a long history of applications in industry, it has only recently been introduced into IC fabrication as an alternative means of depositing BEOL metallic conductors. Since this represents a significant departure from the traditional means of depositing metal using "dry" deposition techniques, it raises many questions regarding its integration into IC manufacturing. We report herein some of the issues confronted during the startup phase in IBM. The anticipated manufacturing issues with electroplating were three-fold: (1) tool selection, (2) fab integration, and (3) process control. The tool selection issue is significant because it plays an important role in determining the cost-of-ownership. The lack of multiple suppliers of electroplating tools suitable for incorporation into a manufacturing process was a significant concern, particularly for reasons of second sourcing. The fab integration issue primarily centered on two items: (a) risk of copper contamination as a result of the electroplating operation, and, (b) waste treatment considerations including environmental impact and cost. Finally, the question of "process control" is particularly significant since integration of plating into high-volume manufacturing requires the ability to control film deposit quality over the course of thousands of depositions with minimal operator intervention.